Lightly grease or line a 9x13-inch baking dish. Without separating the rolls, slice the entire sheet of Hawaiian rolls in half horizontally using a serrated knife.
Place the bottom half of the rolls into the prepared baking dish.
Layer the sliders: Cover the bread with cheese slices evenly over the bottom rolls to create a barrier that helps keep the buns from becoming soggy. Spread the BBQ pulled pork over the cheese. Top with dill pickle slices. Add the second layer of cheese over the pork. Add the top rolls.
Make the butter topping: Stir together the melted butter and garlic powder, then brush the mixture evenly over the tops of the rolls. Sprinkle with the chopped parsley, if using.
Cover loosely with aluminium foil and bake for 10 minutes. Remove the foil and continue baking for 5–8 minutes, or until the cheese is fully melted and the tops are golden brown.
Let the sliders rest for about 5 minutes before slicing along the roll lines into individual sliders.
Serve warm with the prepared coleslaw spooned onto each slider or on the side, along with additional BBQ sauce for dipping if desired.
Notes
Drain the pork: Remove excess cooking liquid before assembling.
Go light on sauce: Coat the pork without making it overly wet.
Layer the cheese: Add cheese below and above the pork for the best melt.
Keep coleslaw crisp: Add it after baking, not inside the sliders.
Store leftovers: Refrigerate in an airtight container for up to 3 days.